comparison between IT solutions?

Hi all

I am always confused when a company or a person asks me the following questions:

Which the best antivirus we can install on their company or their home PC?

When I ask some specialist friends, I got different answers some of them prefer Kaspersky or AVG or AViRA or Node32 or Norton or Mcafee?..

Which brand name we have to choose for our server, is it HP or Dell?

Which brand name we have to choose for our workstations, is it HP or Acer?

As I am System Specialist, I should got a convinced answer, so how I can answer any company which antivirus solution is better for them or which server they should buy?

Is there any company doing this comparison between these solutions?